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PubMed2001

Effects of beta-carotene supplementation for six months on clinical and laboratory parameters in patients with cystic fibrosis.

BACKGROUND: Patients with cystic fibrosis (CF) have significantly decreased plasma concentrations of nutrient antioxidant vitamins, especially of beta-carotene, which is thought to result from fat malabsorption and chronic pulmonary inflammation. The aim of this double blind, placebo controlled study was to investigate the effect of oral beta-carotene supplementation for six months on clinical parameters. METHODS: Twenty four patients with CF were randomised to receive beta-carotene 1 mg/kg/day (maximum 50 mg/day) for three months (high dose supplementation) and 10 mg/day for a further three months (low dose supplementation) or placebo. At monthly follow up visits the plasma beta-carotene concentration, total antioxidant capacity, malondialdehyde (MDA) as a marker of lipid peroxidation, and clinical parameters (Shwachmann-Kulczycki score, body mass index (BMI), height, and lung function (FEV(1))) were assessed. The number of pulmonary exacerbations requiring antibiotic treatment (in days) three months before and during the study were evaluated. RESULTS: The plasma concentration of beta-carotene increased significantly to the normal range during the three months of high dose supplementation (baseline 0.08 (0.04) micromol/l to 0.56 (0.38) micromol/l; p<0.001) but decreased to 0.32 (0.19) micromol/l in the period of low dose supplementation. Initially raised plasma levels of MDA fell to normal levels and the total antioxidant capacity showed a non-significant trend towards improvement during high dose supplementation. Antibiotic treatment decreased significantly in the supplementation group from 14.5 (14.9) days/patient during the three months before the study to 9.8 (10.3) days/patient during high dose supplementation (p=0.0368) and to 10.5 (9.9) days/patient during low dose supplementation, but increased in the placebo group. The Shwachmann-Kulczycki score, lung function, and BMI did not show any changes in either of the treatment groups. No adverse events were observed during the study period. CONCLUSION: Oral beta-carotene supplementation in a dose of 1 mg/kg/day only was effective in normalising the plasma concentration of beta-carotene and resulted in a decrease in pulmonary exacerbations. These data suggest that patients with CF may benefit clinically from supplementation with beta-carotene and further studies are warranted.

Adolescent↗

PubMed2005

Amphiphilic pyridinium salts block TNF alpha/NF kappa B signaling and constitutive hypersecretion of interleukin-8 (IL-8) from cystic fibrosis lung epithelial cells.

Cystic fibrosis (CF) is a common, lethal genetic disease, which is due to mutations in the CFTR gene. The CF lung expresses a profoundly proinflammatory phenotype, due to constitutive hypersecretion of IL-8 from epithelial cells lining the airways. In a systematic search for candidate drugs that might be used therapeutically to suppress IL-8 secretion from these cells, we have identified a potent and efficacious series of amphiphilic pyridinium salts. The most potent of these salts is MRS2481, an (R)-1-phenylpropionic acid ester, with an IC50 of ca. 1microM. We have synthesized 21 analogues of MRS2481, which have proven sufficient to develop a preliminary structure-activity relationship (SAR). For optimal activity, we have found that the ester must be connected to the pyridinium derivative by an eight-carbon chain. An optical isomer of the lead compound, containing an (S)-1-phenylpropionic acid ester, has been found to be a much less active. The mechanism of action of MRS2481 appears to involve inhibition of signaling of the NF(kappa)B and AP-1 transcription factors to the IL-8 promoter. MRS2481 is a potent inhibitor of TNFalpha-induced phosphorylation and proteosomal destruction of I(kappa)B(alpha). Inasmuch as I(kappa)B(alpha) is the principal inhibitor of the NF(kappa)B signaling pathway, preservation of intact I(kappa)B(alpha) would serve to keep the IL-8 promoter silent. We also find that MRS2481 blocks TNF(alpha)-activated phosphorylation of JNK, the c-JUN kinase. The IL-8 promoter is also activated by an AP-1 site, which requires a phospho-c-JUN/c-FOS dimer for activity. We therefore interpret these data to suggest that the mechanism of MRS2481 action is to inhibit both NF(kappa)B and AP-1 signaling on the IL-8 promoter. Given the medicinally promising properties of water-solubility, potency in the low muM concentration range, and high efficacy, we anticipate that MRS2481, or a further optimized derivative, may find an important place in the armamentarium of pharmaceutical strategies yet to be arrayed against the inflammatory phenotype of the CF lung.

Cystic Fibrosis↗

PubMed1994

Bromide pharmacokinetics in cystic fibrosis.

OBJECTIVE: Individuals with cystic fibrosis (CF) have altered kinetics for a number of drugs, most often an increased volume of distribution (Vd) per body weight and increased clearance per body weight. To further evaluate those differences, we studied bromide kinetics (Vd, elimination rate constant, and clearance) and body mass index in eight adults with mild-to-moderate forms of CF, 21 obligate carriers of the CF gene, and 21 healthy controls. Bromide distribution approximates the extracellular fluid volume and bromide is excreted unchanged by the kidney. DESIGN: Individuals were given a single oral dose of bromide (50 mg/kg), and serum bromide concentrations were measured over 4 weeks. Bromide pharmacokinetics (Vd, elimination rate constant, and clearance) were determined using a one-compartment model with first-order kinetics. Body mass index was determined for each individual. RESULTS: Individuals with CF had a significantly greater lean body mass per kilogram as estimated by body mass index compared with individuals in the obligate carrier and control groups. The mean (+/- SD) Vd per kilogram for the CF group (311 +/- 29 mL/kg) was significantly greater than that of the obligate carrier group (261 +/- 26 mL/kg) and the control group (274 +/- 30 mL/kg). However, the mean (+/- SD) Vd per square meter for the three groups was similar. The mean elimination rate constant for the CF group (3.55 +/- 0.98 x 10(-3)/h) was significantly greater compared with the mean elimination rate constant for the obligate carrier group (2.55 +/- 0.36 x 10(-3)/h) and the control group (2.58 +/- 0.49 x 10(-3)/h). The mean (+/- SD) clearance per kilogram was also significantly greater for the CF group (1095 +/- 283 microL/kg per hour) compared with the obligate carrier group (664 +/- 100 microL/kg per hour) and the control group (700 +/- 115 microL/kg per hour). CONCLUSIONS: These findings indicate that individuals with CF have a greater Vd per kilogram for bromide and drugs that distribute in the extracellular fluid volume because of their greater lean body mass per kilogram. The findings also suggest that individuals with CF have a greater renal clearance of bromide and presumably of other anionic drugs excreted by the kidney. The results emphasize the importance of body composition in drug disposition.

Adolescent↗

PubMed2000

Monitoring of 25-OH vitamin D levels in children with cystic fibrosis.

BACKGROUND: Patients with cystic fibrosis are at risk for malabsorption of fat-soluble vitamins, and those with low 25-OH vitamin D levels have a higher risk of low bone mineral density and long-term skeletal complications. It is currently recommended that vitamins A and E be monitored yearly; however, no recommendations exist for 25-OH vitamin D. Because all three vitamins are fat-soluble, the hypothesis in the current study was that low levels of vitamins A and E could identify patients at risk for low 25-OH vitamin D, so that 25-OH vitamin D measurements could be obtained in only selected circumstances. METHODS: Forty (21 girls) patients with CF, age 10.5 +/- 3.9 (SD) years, were assessed in a cross-sectional survey for ideal weight for height (percentage of predicted), spirometry (percentage of predicted FEV1, 33/40 patients), and serum levels of vitamins A, E, 25-OH vitamin D, and cholesterol (37/40 patients). RESULTS: Nine (22.5%) of 40 patients were malnourished (percentage of predicted ideal weight for height <85%), 7 (21.2%) of 33 had moderate to severe lung disease (FEV1 <60%), 4 (10%) of 40 had low levels of vitamin A, 3 (7.5%) of 40 had low vitamin E levels, 4 (10.8%) of 37 low vitamin E/cholesterol levels, and 4 (10%) of 40 had marginal or low levels of 25-OH vitamin D (<40 mmol/l). The patients with low 25-OH vitamin D were older, with no child < 12 years of age having a 25-OH vitamin D level less than 40 mmol/l. They also had lower vitamin E and vitamin E/cholesterol levels than those with normal 25-OH vitamin D levels. The groups did not differ in percentage of predicted ideal weight for height, lung function, or vitamin A levels. The best positive predictor for 25-OH vitamin D less than 40 mmol/l was low vitamin E (66.7%), with a negative predictive value of 94.6%. 25-OH vitamin D levels correlated with vitamin E/cholesterol levels (r = 0.41, P < 0.01) and weakly with vitamin E levels (r = 0.28, P < 0.08), but not with vitamin A levels. CONCLUSIONS: These results suggest that children aged less than 12 years and older children with normal vitamin E levels are especially unlikely to have low 25-OH vitamin D levels, and this measure can therefore be omitted. In contrast, those children with low vitamin E levels may warrant monitoring.

Adolescent↗

PubMed1994

Psychosocial functioning of young adults with cystic fibrosis and their families.

BACKGROUND: The psychosocial functioning of adolescents and young adults with cystic fibrosis still living in the parental home was investigated. With its proven genetic aetiology cystic fibrosis is an ideal model with which to assess the impact of a chronic and life threatening disorder on family and individual psychological and social functioning. METHODS: Twenty nine patients with cystic fibrosis and their families were compared with those of 27 patients with anorexia nervosa and 31 well controls. Assessments were made using self reporting, interview, and observational methods. RESULTS: Most patients with cystic fibrosis were in robust psychological health and only differed from their healthy peers in that they were much less likely to be in employment. Mothers of patients with cystic fibrosis or anorexia nervosa were more likely than the mothers of the well group to be emotionally distressed, although this was not so for fathers. Young people in both illness groups were more likely to have parents with high levels of expressed emotion. Most families of patients with cystic fibrosis had good problem solving abilities. CONCLUSIONS: In spite of the burden of illness in cystic fibrosis psychological functioning in many respects matches that of well young people.

Adolescent↗

PubMed1991

New insights on gastro-oesophageal reflux in cystic fibrosis by longitudinal follow up.

A higher frequency (25%) of gastrooesophageal reflux (GOR) has been previously reported in patients over 5 years old with cystic fibrosis compared with controls without cystic fibrosis. It was believed that GOR was caused by the complications of cystic fibrosis. We looked for GOR in all 26 children younger than 60 months who had cystic fibrosis diagnosed. They had a classical genetic profile and the usual scattered clinical manifestations for age. GOR was confirmed in 21 (81%): 20 by abnormal pH tracings and in one on a clinical basis. After at least one month of adjusted cystic fibrosis treatment, antireflux treatment (cisapride) was given to 16 patients and variables of GOR improved dramatically. Weight gain was significant and recurrent cough and wheeze disappeared. One year later half of the patients still suffered from GOR. GOR is a major problem in the early life of those with cystic fibrosis and is not the consequence of either respiratory or gastrointestinal complications as it improves with age whereas cystic fibrosis becomes worse with age.

Child, Preschool↗

PubMed1975

Contribution of inhomogeneity of lung units to the maximal expiratory flow-volume curve in children with asthma and cystic fibrosis.

Normal children as well as those with asthma and cystic fibrosis were studied to assess the contribution of lung zones emptying at different rates to the curvilinearity of the maximal expiratory flow-volume curve. Lung volumes, maximal expiratory flow-volume curves breathing air and then breathing a helium-oxygen mixture, and single-breath nitrogen washouts were measured. Forced expiratory maneuvers from lung volumes near functional residual capacity were performed to produce transients of flow exceeding maximal flow defined by the full flow-volume curve. Normal children and those with asthma and mild cystic fibrosis had small or no transients. Those with severe cystic fibrosis had large transients as well as increased phase I on the nitrogen washout curves. These large transients were associated with increased curvilinearity of the maximal expiratory flow-volume curve and smaller than normal flow response breathing helium. In severe cystic fibrosis, the large transients suggest sequential emptying of fast and slow spaces, which influences the shape of the maximal expiratory flow-volume curve. The fast space could be due to compression of an enlarged anatomic dead space. Any time constant inequality between parenchymal units present in asthma and mild cystic fibrosis does not appear to contribute significantly tof the shape of the maximal expiratory flow-volume curve.

Adolescent↗

PubMed2006

[Analysis of DNA samples by Abbott Commercial Tests for cystic fibrosis].

The use of commercial tests (Abbott) for cystic fibrosis, version 2 (CFv. 2) and 3 (CFv. 3) and analysis of reaction products by capillary electrophoresis and genotyping on an ABI PRISM 310 genetic analyzer (Applied Biosystems) are presented, along with the results of test validation by concurrent processing of DNA samples on a Light Cycler (Roche Diagnostics) and INNO-LIPA CFTR 19 multiparameter screening test (Innogenetics). The new Abbott commercial test for cystic fibrosis, CFv. 3, allows for determination of the exact number of the potential gene mutations (33 mutations). Other mutations may be present but cannot be established by using this test. Distribution frequency of CFTR gene mutations varies in populations, and this test covers the most frequent mutatiocs in the world. Based on the results obtained by validation, the use of this test is recommended for the following reasons: - the diagnosis of cystic fibrosis is reliable and relatively inexpensive since the reaction products allow for the most current analysis by means of capillary electrophoresis, and computer data processing which will soon enable routine sequencing and thereby determination of point mutations, - it is possible to use very small quantities of isolated DNA and to directly apply microvolumes of blood with EDTA, and - identification of a large number of current mutations has been made possible.

Cystic Fibrosis↗

PubMed1999

Blood concentrations of pancreatitis associated protein in neonates: relevance to neonatal screening for cystic fibrosis.

AIM: To determine whether pancreatitis associated protein (PAP) is a marker for cystic fibrosis which could be used in neonatal screening for the disease. METHODS: PAP was assayed on screening cards from 202,807 neonates. Babies with PAP > or = 15 ng/ml, or > or = 11.5 ng/ml and immunoreactive trypsinogen (IRT) > or = 700 ng/ml were recalled for clinical examination, sweat testing, and cystic fibrosis transmembrane regulator (CFTR) gene analysis. RESULTS: Median PAP value was 2.8 ng/ml. Forty four cases of cystic fibrosis were recorded. Recalled neonates (n = 398) included only 11 carriers. A receiver operating characteristic curve analysis showed that PAP above 8.0 ng/ml would select 0.76% of babies, including all those with cystic fibrosis, except for one with meconium ileus and two with mild CFTR mutations. Screening 27,146 babies with both PAP and IRT showed that only 0.12% had PAP > 8.0 ng/ml and IRT > 700 ng/ml, including all cases of cystic fibrosis. CONCLUSION: PAP is increased in most neonates with cystic fibrosis and could be used for CF screening. Its combination with IRT looks promising.

Acute-Phase Proteins↗

PubMed2000

Inhaled corticosteroids for cystic fibrosis.

BACKGROUND: Maintenance of optimal lung function is an important therapeutic goal in cystic fibrosis as it is lung damage that, in the long term, is responsible for most premature death among affected people. Inhaled corticosteroids are being increasingly used to treat children and adults with cystic fibrosis. The rationale for their use is that they have the potential to reduce lung damage arising from inflammation. However chronic use of inhaled steroids may also have adverse effects. It is thus important to establish the current level of evidence about the potential benefits and harms of this practice. OBJECTIVES: The objective of this review is to assess the effectiveness of regular use of inhaled corticosteroids when compared to no inhaled corticosteroids, in the management of patients with cystic fibrosis. SEARCH STRATEGY: Trials were ascertained from the Cochrane Cystic Fibrosis and Genetic Disorders Specialised Register of Controlled Trials which includes published and unpublished trials identified through electronic databases such as Medline and Embase as well as those identified from handsearching of journals and conference proceedings. Pharmaceutical companies manufacturing inhaled corticosteroids were also contacted to identify any trials of inhaled corticosteroids in cystic fibrosis. Date of the most recent search of the Group's specialised register: November 1999. SELECTION CRITERIA: All trials, both published and unpublished, in which inhaled corticosteroids were compared to either placebo or standard treatment in patients with cystic fibrosis. Trials employing random treatment allocation and those using quasi-random allocation methods such as alternate allocation to treatment and control group were included. DATA COLLECTION AND ANALYSIS: The following outcomes were assessed: objective measures of lung function, respiratory exacerbations, use of intravenous antibiotics, hospital admissions, nutritional status, symptoms, quality of life, survival and frequency of adverse effects. Methodological quality of trials was assessed independently using established criteria by two reviewers, who also extracted relevant data independently using standard proformas. Differences were resolved by discussion. MAIN RESULTS: Nine trials were identified reporting the use of inhaled steroids in 266 subjects aged between seven and 45 years with cystic fibrosis. Methodological quality was difficult to assess from published information, specifically with respect to concealment of allocation and method used to generate random sequence. Trials were heterogeneous with respect to inclusion criteria, specifically age, severity of pulmonary involvement, clinical diagnosis of asthma and pulmonary colonisation with Pseudomonas aeruginosa. Trials also differed in type and duration of treatment. Beclomethasone was given for periods of between four and 22 weeks in four trials, budesonide for six weeks and six months respectively in two, and fluticasone for periods of between six weeks and two years in the remaining three. Measures of the volume of air breathed out on a forcible expiration (forced expiratory volumes) were reported in most trials but these data could not be combined for this review partly because reports differed in the way data were summarised and partly because some data were not included in published reports. Outcomes of potentially greater relevance to affected individuals such as nutritional status or quality of life were not reported in any trial. Survival was not reported in any trial, but this may reflect the fact that maximum duration of follow up was too short to allow this outcome to be meaningfully assessed. Adverse effects were systematically documented in only two trials. Although one trial was halted prematurely because a proportion of all those taking part had acquired chronic lung infections with Pseudomonas aeruginosa, no conclusions can be reached from this one small trial as to whether this risk is increased as

Administration, Inhalation↗

PubMed1983

Lipids of gastric secretion in patients with cystic fibrosis.

Lipids were investigated in gastric secretions of patients with cystic fibrosis and of normal individuals. Organic extracts from dialyzed and lyophilized samples were fractionated on silicic acid columns into neutral lipids, glycolipids and phospholipids. The lipids contained in each fraction were separated into individual components by thin-layer chromatography and quantitated. The gastric secretions of patients with cystic fibrosis contained 80-140% more lipids than those of normal individuals, exhibited an elevated level of neutral lipids and contained alkylglycerols and alkylacylglycerols. The level of glycolipids was higher in normal gastric secretions. The phospholipids of cystic fibrosis secretions exhibited about 50% lower content of lysophosphatidylcholine, lysophosphatidylethanolamine and lysophosphatidylserine. The glycosphingolipids of both types of samples contained mono-, di- and trihexosylceramides. The major glyceroglucolipid of normal gastric secretions was tetraglucosyl glyceroglucolipid, whereas hexa- and octaglucosyl glyceroglucolipids were predominant in cystic fibrosis samples. The sulfated glyceroglucolipids in cystic fibrosis samples were lower than those of normal secretions and represented only 4-37% of total glyceroglucolipid, whereas in normal secretion sulfated glyceroglucolipids averaged 50-62%.

Cholesterol↗

PubMed2001

Growth hormone decreases protein catabolism in children with cystic fibrosis.

Despite aggressive nutritional therapy, low body weight and protein catabolism are common problems in children with cystic fibrosis. Previous studies by our group and others have demonstrated improvement in both height and weight in children with cystic fibrosis who were treated with human recombinant GH, and our group has recently documented improved clinical status and lean tissue mass as well. The purpose of this report is to summarize our findings of the effect of GH on whole body protein kinetics in cystic fibrosis and to relate these findings to changes in TNF-alpha levels. We conducted a 1-yr study of 19 prepubertal children with cystic fibrosis (age 7-12 yr, all <94% of ideal body weight). Ten children were randomly assigned to take daily injections of GH (0.3 mg/kg.wk), and nine were randomly assigned to be controls. Baseline results from the subjects with cystic fibrosis were compared with results obtained from nine age- and gender-matched healthy children. Whole body protein turnover was measured at baseline and every 6 months using the stable isotope [1-(13)C]leucine and mass spectrometric analysis. Leucine rate of appearance, a measure of protein catabolism, was similar in both cystic fibrosis subgroups at baseline and was significantly higher than in the control children without cystic fibrosis. Treatment with GH resulted in a significantly lower leucine rate of appearance, as well as significantly lower leucine oxidation. The rate of protein synthesis, as calculated from these numbers, actually decreased in the cystic fibrosis subgroup. TNF-alpha levels were higher in both cystic fibrosis subgroups than in controls and correlated with leucine rate of appearance. The results of this study suggest that one reason GH improves body weight and lean tissue mass is due to improved whole body protein catabolism and improved efficiency of whole body protein kinetics.

Algorithms↗

PubMed1986

Misclassification problems in diagnosis-related groups. Cystic fibrosis as an example.

Under the Medicare prospective payment system, which is based on diagnosis-related groups, patients with certain diseases may be inappropriately classified. To study this problem using cystic fibrosis as an example, we examined discharge-abstract data from 14 cystic fibrosis centers in a comparison of resource-use requirements by patients with cystic fibrosis and other patients in the same diagnosis-related group. There were 1763 patients with cystic fibrosis and 25,628 other patients in the 87 diagnosis-related groups that contained at least one patient with cystic fibrosis. For the eight diagnosis-related groups in which patients with cystic fibrosis were classified most often, the average length of stay of patients with cystic fibrosis was 14.9 days, as compared with an average of 8.3 days for the other patients (P less than 0.001). For three hospitals, we were able to convert charges to costs. The average cost of treating patients with cystic fibrosis was $7,262, as compared with $2,908 for all other patients in the same diagnosis-related group (P less than 0.001). The ratio between the costs of treating patients with cystic fibrosis and other patients (2.5) was greater than the ratio between the lengths of stay for the two groups (1.8), reflecting the more intense use of resources by the patients with cystic fibrosis. A possible solution to the problem of misclassification is to define one or more new diagnosis-related groups for cases of cystic fibrosis or determine a new location within the diagnosis-related group system so that patients with cystic fibrosis can be classified with patients who use similar amounts of resources.

Costs and Cost Analysis↗

PubMed1985

A morphologic and fluorophotometric analysis of the corneal endothelium in type I diabetes mellitus and cystic fibrosis.

Seven patients with type I diabetes mellitus (Group 1), seven with normoglycemic cystic fibrosis (Group 2), seven with hyperglycemic cystic fibrosis (Group 3), and ten age-matched control subjects underwent corneal fluorophotometry and quantitative specular microscopy. Group 1 had background microangiopathic retinopathy but no evidence of proliferative disease by fluorescein angiography. Significant increases in mean corneal endothelial permeability and mean pump rate occurred in Group 1, indicating a defect in the endothelial barrier function early in type I diabetes mellitus. Similar significant increases in mean corneal endothelial permeability and mean pump rate occurred in both cystic fibrosis groups. The greatest increase was found in Group 3, suggesting a primary defect in the endothelial barrier function in cystic fibrosis, aggravated by the hyperglycemic state. No morphologic abnormalities were noted in Group 1, but both cystic fibrosis groups had smaller mean cell areas than did the control group. There were significant differences in the morphologic and functional correlations between Groups 1 and 3, suggesting different mechanisms for the increased endothelial permeability in these two disorders.

Adult↗

PubMed2002

[Lung transplantation in cystic fibrosis].

Lung transplantation should be considered in cystic fibrosis patients with end-stage lung disease. The optimal time for pretransplantation evaluation rely on spirometric and gazometric criteria, as well as on the decline of pulmonary function and the degree of quality of life's impairment. Non-pulmonary complications of cystic fibrosis such as diabetes, osteoporosis and poor nutritional status should be evaluated, prevented and treated. Post-transplantation survival of cystic fibrosis patients is not different from that of other groups of pulmonary transplanted subjects, and is surprisingly not affected by chronic bacterial and fungal colonization of the airways.

Cystic Fibrosis↗

PubMed1994

Insulin sensitivity and insulin clearance in cystic fibrosis patients with normal and diabetic glucose tolerance.

OBJECTIVE: We studied glucose metabolism and insulin kinetics in cystic fibrosis patients with diabetic and normal glucose tolerance. DESIGN: Measurements of blood glucose and serum free insulin concentrations during hyperinsulinaemic normoglycaemic clamp and post-clamp insulin decay, followed by the calculation of insulin sensitivity (M-value and M/I ratio), insulin clearance rate, serum half-life and apparent distribution space for insulin. SUBJECTS: Cystic fibrosis patients, age range 20-29 years, with diabetes mellitus (n = 10) and normal glucose tolerance (n = 10), and 10 age-matched control subjects. RESULTS: During the glucose clamp, diabetic cystic fibrosis patients needed less glucose than cystic fibrosis patients with normal glucose tolerance and control subjects (M-value), and steady-state serum insulin concentrations were lower in cystic fibrosis patients with diabetic and normal glucose tolerance than in control subjects. The quantity of glucose metabolized per unit of serum insulin concentration (M/I ratio) was similar in the three study groups (median approximately 145 (mumol/kg/min)/(nmol/l); range 70-252). Insulin clearance rates were higher in cystic fibrosis patients with diabetic (24.4 (19.3-29.9) ml/kg/min) and normal (22.6 (14.9-28.4) ml/kg/min) glucose tolerance than in control subjects (17.5 (15.9-24.2) ml/kg/min). Although insulin clearance rates were inversely related to body mass index (R(S) = -0.59, P < 0.001), the higher insulin clearance rates in CF patients cannot be accounted for solely by differences in body mass index since the insulin clearance rates were similarly increased in patients with body mass index above and below 20 kg/m2 (22.7 (14.9-28.4) and 24.4 (19.3-29.9) ml/kg/min, respectively). Serum half-lives for insulin were shorter in cystic fibrosis patients (approximately 4.3 (3.2-7.2) min) than in control subjects (5.9 (3.8-12.5) min), whereas the apparent distribution spaces for insulin were similar in the three study groups (approximately 150 (88-391) ml/kg). CONCLUSIONS: Insulin sensitivity, calculated as the quantity of glucose metabolized per kg body weight per unit of serum insulin concentration, is normal in cystic fibrosis patients with normal glucose tolerance and with well controlled diabetes mellitus. The insulin clearance rate is increased in cystic fibrosis patients with diabetic and normal glucose tolerance, owing to a shorter serum half-life of insulin, whereas the apparent distribution space for insulin is normal.

Adult↗

PubMed1987

Hospital epidemiology of Pseudomonas aeruginosa from patients with cystic fibrosis.

Pseudomonas aeruginosa colonizes the respiratory tract of most older patients with cystic fibrosis. The means by which these bacteria are acquired and the risk for patient-to-patient spread among subjects with cystic fibrosis are poorly understood. We studied the spread of Ps. aeruginosa within a hospital environment. Pseudomonas was rarely recovered from the inanimate environment surrounding patients with cystic fibrosis or from hand or rectal cultures of patients who were colonized in the oropharynx. There was transient cross-colonization with Ps. aeruginosa between patients with cystic fibrosis sharing a hospital room in three of seven pairs studied. In all cases the "new" isolate was recoverable only once and was not found during a 2-year follow-up. Three of four sibling pairs with cystic fibrosis shared the same Ps. aeruginosa serotype(s). The risk of sustained cross-colonization by Ps. aeruginosa between patients with cystic fibrosis appears to be minimal, except under conditions of prolonged close contact.

Adolescent↗

PubMed2005

Base treatment corrects defects due to misfolding of mutant cystic fibrosis transmembrane conductance regulator.

BACKGROUND & AIMS: The most common form of the disease-causing cystic fibrosis transmembrane conductance regulator mutation, DeltaF508, leads to a misfolded protein that undergoes endoplasmic reticulum-associated degradation. Retrieval of misfolded protein from the cis-Golgi or pre-Golgi intermediate compartment is a critical factor in endoplasmic reticulum retention and degradation of DeltaF508 protein. Therefore, the inhibition of retrograde Golgi-to-endoplasmic reticulum traffic by the alkalinization of Golgi lumen may permit functional DeltaF508 protein to reach the cell surface. METHODS: Functional and biochemical effects of alkaline treatment on misfolded cystic fibrosis transmembrane conductance regulator-induced defects were measured in CFPAC-1 cells, which endogenously express DeltaF508 cystic fibrosis transmembrane conductance regulator, and in CHO cells, which heterologously express DeltaF508 cystic fibrosis transmembrane conductance regulator. The animal survival rate and the functional expression of cystic fibrosis transmembrane conductance regulator proteins were analyzed in homozygous DeltaF508 mice after chronic treatment with weak base NaHCO3. RESULTS: In CFPAC-1 and CHO cells, intracellular alkalization by reducing carbon dioxide concentrations in a carbon dioxide incubation chamber or intra-Golgi alkalization by bafilomycin A1 treatment increased the membrane expression of DeltaF508 protein and cystic fibrosis transmembrane conductance regulator-dependent anion transport. Notably, chronic administration of NaHCO3 increased the long-term survival of homozygous DeltaF508 mice and induced the functional expression of cystic fibrosis transmembrane conductance regulator in the luminal membrane of intestinal epithelium. CONCLUSIONS: We found that base treatments correct misfolded cystic fibrosis transmembrane conductance regulator-induced defects in vitro and in vivo. These results imply that the alkalization of intracellular compartments, in particular, Golgi or pre-Golgi intermediate compartments, can be a potential therapeutic target for the loss-of-function type of conformational diseases.

1-Methyl-3-isobutylxanthine↗